If you are running your Redhat/Centos or Fedora machine in an enterprise environment you may be sitting behind a network proxy server like squid.
If you try and update or install software it will fail with timeouts or errors contacting the repository mirrors.
To configure YUM to work with your proxy server you need to add the following line to your /etc/yum.conf file.
Anonymous proxy configuration:
proxy=http://yourproxyip:port/
If your proxy server requires authentication add the following lines to your /etc/yum.conf file instead.
proxy=http://yourproxyip:port/ proxy_username=youruser proxy_password=yourpassword
You will be able to update and install software now, give it a go!
After split brain has been detected, one node will always have the resource in a StandAlone connection state. The other might either also be in the StandAlone state (if both nodes detected the split brain simultaneously), or in WFConnection (if the peer tore down the connection before the other node had a chance to detect split brain).
At this point, unless you configured DRBD to automatically recover from split brain, you must manually intervene by selecting one node whose modifications will be discarded (this node is referred to as the split brain victim). This intervention is made with the following commands:
# drbdadm secondary resource
# drbdadm disconnect resource
# drbdadm -- --discard-my-data connect resource
On the other node (the split brain survivor), if its connection state is also StandAlone, you would enter:
# drbdadm connect resource
You may omit this step if the node is already in the WFConnection state; it will then reconnect automatically.
If all else fails and the machines are still in a split-brain condition then on the secondary (backup) machine issue:
drbdadm invalidate resource
The best way to learn Recital is to build some applications. The developers of Recital have written a book "Recital Essentials" which you can read here.
So, to create and configure Recital ODBC datasources, you need to use the Window 32 bit ODBC Data Source Administrator or Recital's own Recital Universal ODBC Manager (32-bit).
The Window 32 bit ODBC Data Source Administrator is %windir%\SysWOW64\odbcad32.exe.
The Recital Universal ODBC Manager (32-bit) can be accessed from the Control Panel (icon view).
APPEND FROM TYPE CSV <file-name.csv>The TYPE keyword has now been enhanced to support a comma separated values (CSV) format
This article looks at After Image Journaling and audit trails in Recital using SET JOURNAL and associated commands.
Overview
After Image Journaling, used in conjunction with a structured backup policy is an effective disaster recovery solution. Any transaction that takes place on a table that is being journaled is logged in the journal file. In the event of a disk crash or similar event in which the table is lost, the journaled transactions can be reapplied to the latest backup copy of the table. Alternatively or additionally, the journal can be used to provide an audit trail to all modifications made to the table data.
NOTE: Recital also provides Before Image Journaling via BEGIN TRANSACTION / END TRANSACTION blocks, allowing unsuccessful transactions to be rolled back to a set saved state.
SET JOURNAL and RECOVER
Regular backups are an essential routine for any system, but in high-transaction environments restoration of the latest backup can still mean a major loss of data. After image journaling can successfully be used as part of your disaster recovery strategy to minimize data loss and down time. Recital after image journaling functionality is based on the use of the SET JOURNAL and RECOVER commands.
SET JOURNAL
SET JOURNAL TO [<.dbj filename> | ()] SET JOURNAL ON | OFF | ( )
The SET JOURNAL command is used to enable the After Image Journaling and audit trail for the active table. The TO <.dbj filename> clause associates the specified transaction journal file with the active table. If the journal file does not exist, it will be created. The filename can be substituted with a <expC>, enclosed in round brackets, which returns a valid filename. If no file extension is specified, ‘.dbj’ is used. When specifying a journal file, it is recommended that the journal file is stored on a different disk than that which the table is stored on, so that if a fatal disk error occurs, then the journal file will not be lost along with the table.
//Enable journaling for the southwind!orders table open database southwind use orders set journal to /journals/ord_journ
The <.dbj filename> is a standard table. It contains seven
fields that are specific to a journal file, followed by the first
249 fields of the associated table.
The first seven fields in the journal are:
|
Field |
Type |
Display |
Storage |
Description |
|
AUD_DATE |
Date |
8 | 10 * |
4 |
The date on which the transaction was performed. |
|
AUD_TIME |
Character |
8 |
8 |
The time at which the transaction was performed, in the format HH:MM:SS. |
|
AUD_TERM |
Character |
12 |
12 |
The name of the terminal from which the transaction was performed |
|
AUD_UID |
Short |
5 |
2 |
The ID of the user who performed the transaction. |
|
AUD_GID |
Short |
5 |
2 |
The group ID of the user who performed the transaction. |
|
AUD_CMD |
Short |
4 |
2 |
The command number of the transaction performed from the command table below |
|
AUD_RECNO |
Integer |
7 |
4 |
The record number in the associated table which the transaction was performed on. |
* Dependent on SET CENTURY setting.
The AUD_CMD Command Reference Numbers are as follows:
|
Command |
Number |
|
DELETE |
14 |
|
RECALL |
36 |
|
REPLACE |
41 |
|
BROWSE |
6 |
|
CHANGE |
8 |
|
EDIT |
17 |
|
INSERT |
26 |
|
APPEND |
5 |
|
READ |
35 |
Since journal files are standard Recital tables, you can use standard Recital commands such as the REPORT command to print audit trails, transaction logs, etc.
//Enable journaling for the southwind!orders table open database southwind use orders set journal to /journals/ord_journ //.. transactions close data //View journaled records use /journals/ord_journ.dbj
Click image to display full size
Fig 1: Journal Record Example.
The SET JOURNAL TO command without a <.dbj filename> specified closes the active journal file and no further journaling will take place on the active table until the SET JOURNAL TO <.dbj filename> is reissued.
The journaling features are mainly used with shared tables. It should be noted that there is an overhead in enabling transaction journaling, as records updated in a table are also written to the journal file. When records are appended into a journal file, locking is automatically performed so that multiple users can update the journal concurrently. The associated table must be opened shareable for this to occur. Each table can have a journal file associated with it.
The SET JOURNAL ON | OFF command enables or disables transaction journaling. This command is primarily used in applications where journaling can be disabled for a certain class of operations. By default, SET JOURNAL is ON, but no journal files are set.
NOTE: Only the first 249 fields of a table can be journaled: subsequent fields are ignored. The maximum number of fields in a Recital table is 256.
RECOVER
RECOVER FROM <.dbj filename> | ()
The RECOVER command uses the journal file to reapply lost transactions to a previous backup of the data after a fatal error such as a disk head crash. The FROM clause specifies the journal file to use. The file name can be substituted with an <expC>, enclosed in round brackets, which returns a valid filename. If no file extension is specified, then ‘.dbj’ is assumed.
Regular backups are essential to the successful use of After Image Journaling. It is also very important to reinitialize the journal file after each backup: either open the journal file as you would a normal table and use the ZAP command, or delete the file completely. If a fatal error occurs, such as a disk head crash, the table and index files must be restored from a backup, then the RECOVER command executed. RECOVER will reapply' all of the transactions in the journal file to the table, and update the indexes. After the RECOVER command has completed, you can continue with normal processing.
//Create a backup of the southwind!orders table //...backup table and associated files //Reinitialize the journal file erase /journals/ord_journ.dbj //Enable journaling for the southwind!orders table open database southwind use orders set journal to /journals/ord_journ //.. transactions //Restore the backup of the southwind!orders table //...restore //Open the restored backup open database southwind use orders //Reapply the transactions using the journal recover from /journals/ord_journ.dbj //Now, enable the journal file again or //restart with a new backup
Journaling Memo Fields
By default, memo fields - variable length text fields - are not journaled due to the possible storage overhead of multiple copies of potentially large blocks of text. But, if memo journaling is required, the SET MEMOJOURNAL ON command can be used to enable this.
SET MEMOJOURNAL
SET MEMOJOURNAL ON | OFF | ()
The SET MEMOJOURNAL command causes memo fields to be journaled when journaling is set on a table. This command allows the optional logical expression <expL> to be evaluated. If a value of .T. is returned, MEMOJOURNAL is set ON. If a value of .F. is returned, MEMOJOURNAL is set OFF. By default SET MEMOJOURNAL is OFF.
Like a normal Recital table, the journal holds only a pointer to a data block in an associated memo file, not the actual memo data itself. The journal's memo file has a file extension of .dbm rather than the standard Recital .dbt. Therefore, if the journal is being opened as a table, in order to view the journal's memo data, the SET MEMOEXT command should be used.
//Enable journaling for the southwind!suppliers table open database southwind use suppliers set journal to /journals/sup_journ //.. transactions close data //Set filename extension for memo file set memoext to '.dbm' //View journaled records use /journals/sup_journ.dbj
Summary
The After Image Journaling enabled by the SET JOURNAL and RECOVER commands can be used in conjunction with a strict backup regime to minimize data loss in cases where tables become damaged or irretrievable. Journal files can be accessed like standard Recital tables and provide detailed information about the transactions applied to a table, so can be used for auditing purposes.
This article talks about the log files available in Recital products and how to enable logging when required.
Overview
When discussing a problem with the Recital Support Team, one of the most common requests is that you enable logging and send them the log files produced. Log files along with error files are designed to provide detailed information about Recital processes and the prevailing environment and can be a fast-track to resolving a problem.
Log Files
There are three main types of log file:
- System Log
- Client/Server Communication Logs
- Custom Logs
System Log
The System log is a system-wide all product log. It tracks all login and logout operations from either Recital or the Recital Server. Logout details include the exit code: 0 for an error-free, 'normal' exit and the error number and message when an error has occurred. It also shows the licenses that have been loaded and any license error codes and messages. The system log filename is recital.log.
Client/Server Communication Logs
The Client/Server communication logs track the requests and responses between the Recital Server and its clients. The log files are as follows:
| Filename | Type | Description |
|---|---|---|
|
dbserver.log |
System-wide |
The Recital Server startup log. This logs any problems with the Recital Server startup. |
|
port.log |
System-wide |
The port listener log. The port listener (or portserver) listens on port 8001 for client connection requests and spawns the appropriate server process. |
|
net.log |
Connection |
The netserver log. The netserver is the Recital Server database and 4GL engine. |
|
rsi.log |
Connection |
The Recital Server Interface (RSI) Gateway log. This logs communication with the Database Gateways to SQL databases. |
|
rec.log |
Connection |
The Recital Database Gateway log. The Recital Database Gateway (or recserver) is the SQL database engine for Recital Gateway data access. |
|
mys.log |
Connection |
The MySQL Database Gateway log. |
|
ora.log |
Connection |
The Oracle Database Gateway log. |
|
inf.log |
Connection |
The Informix Database Gateway log. |
|
ing.log |
Connection |
The Ingres Database Gateway log. |
|
pos.log |
Connection |
The PostgreSQL Database Gateway log. |
|
jdb.log |
Connection |
The JDBC Driver Database Gateway log. |
Custom Logs
The Recital/4GL USERLOG() function can be used to log information to a user-specific log file for debugging or audit trail purposes. For full information on this function, please see the USERLOG() documentation.
Enabling Log Files
For instructions on enabling log files for individual products, please follow these links:
- Recital Server for Windows
- Recital Server for Linux
- Recital Server for UNIX
- Recital Server for OpenVMS
- Recital for Linux
- Recital for UNIX
- Recital for OpenVMS
Enabling Log Files: Recital Server for Windows
To enable the system log file for the Recital Universal Application Server for Windows, include the following command in the UAS\config.db file:
set syslogging on
The Recital Server Manager System Logging tab allows for the viewing and resetting of the System log.
Section
Item
Description
System Logging
DateTime
Date and time stamp of the action.
Name
Login name used by connection
Action
Action logged: Login, Logoff, Errot
Details
Details of action
Buttons
Purge
Allows the log file to be reset
Refresh
Refreshes the display
To set up Client/Server logging, use the Recital Server Manager Settings tab to update the server's Registry entries:
The following Log file settings can be configured:
|
Item |
Description |
|---|---|
|
Log files Directory Path |
Enter the directory in which log files will be created. The default is the UAS\log directory. |
|
Enabled |
Check to enable log file creation. |
|
Versions |
Check to enable log file versioning. |
|
Listener |
Click to view the current port listener log file |
|
Server |
Click to view the current netserver log file |
|
Purge |
Click to purge all log files |
Enabling Log Files: Recital Server for Linux
To enable the system log file for the Recital Server for Linux, include the following command in the conf/config.db file:
set syslogging on
To set up Client/Server logging, the Recital Server can be started with the 'logging' parameter, in which case, all relevant logging will take place.
# service startup logging<
Alternatively, one or more of the following environment variables can be added to the dbserver.conf file or set at the Operating System prompt. The Recital Server must be restarted before environment variable changes will be recognized. Each environment variable should be set to the name of a log file.
Environment Variable
Logs Activity of...
UASLOG_PORT
Port Server (db_rsiserver)
UASLOG_NET
(Net) Server (db_netserver)
UASLOG_ORA
Oracle Server (db_oraserver)
UASLOG_INF
Informix Server (db_infserver)
UASLOG_ING
Ingres Server (db_ingserver)
UASLOG_JDB
JDBC Server (db_jdbserver)
UASLOG_REC
Recital Server (db_recserver)
Extract from recital.conf:
UASLOG_PORT="port.log" ; export UASLOG_PORT UASLOG_NET="net.log" ; export UASLOG_NET UASLOG_ORA="ora.log" ; export UASLOG_ORA UASLOG_INF="inf.log" ; export UASLOG_INF UASLOG_ING="ing.log" ; export UASLOG_ING UASLOG_JDB="jdb.log" ; export UASLOG_JDB UASLOG_REC="rec.log" ; export UASLOG_REC
DB_LOGDIR
If the environment variable DB_LOGDIR is set to an existing directory, all log files will be written to this directory. If not, the log files will be created in the bin directory.
DB_LOGDIR is set in the conf/recital.conf file. By default it is set to the log directory:
DB_LOGDIR=${ROI_ROOT}log/ ; export DB_LOGDIR
DB_LOGVER
If the environment variable DB_LOGVER is greater than 0, version numbers are added to the file names. For example, the activity of the first Net Server process will be logged to net.log, the second to net001.log, the third to net002.log etc. up to the maximum value of DB_LOGVER.
DB_LOGVER is set in the conf/recital.conf file:
DB_LOGVER=10; export DB_LOGVER
Enabling Log Files: Recital Server for UNIX
To enable the system log file for the Recital Server for UNIX, include the following command in the conf/config.db file:
set syslogging on
To set up Client/Server logging, the Recital Server can be started with the 'logging' parameter, in which case, all relevant logging will take place.
# service startup logging
Alternatively, one or more of the following environment variables can be added to the <em>dbserver.conf</em> file or set at the Operating System prompt. The Recital Server must be restarted before environment variable changes will be recognized. Each environment variable should be set to the name of a log file.
Environment Variable
Logs Activity of...
UASLOG_PORT
Port Server (db_rsiserver)
UASLOG_NET
(Net) Server (db_netserver)
UASLOG_ORA
Oracle Server (db_oraserver)
UASLOG_INF
Informix Server (db_infserver)
UASLOG_ING
Ingres Server (db_ingserver)
UASLOG_JDB
JDBC Server (db_jdbserver)
UASLOG_REC
Recital Server (db_recserver)
Extract from recital.conf:
UASLOG_PORT="port.log" ; export UASLOG_PORT UASLOG_NET="net.log" ; export UASLOG_NET UASLOG_ORA="ora.log" ; export UASLOG_ORA UASLOG_INF="inf.log" ; export UASLOG_INF UASLOG_ING="ing.log" ; export UASLOG_ING UASLOG_JDB="jdb.log" ; export UASLOG_JDB UASLOG_REC="rec.log" ; export UASLOG_REC
DB_LOGDIR
If the environment variable DB_LOGDIR is set to an existing directory, all log files will be written to this directory. If not, the log files will be created in the bin directory.
DB_LOGDIR is set in the conf/recital.conf file. By default it is set to the log directory:
DB_LOGDIR=${DB_ROOT}log/ ; export DB_LOGDIR
DB_LOGVER
If the environment variable DB_LOGVER is greater than 0, version numbers are added to the file names. For example, the activity of the first Net Server process will be logged to net.log, the second to net001.log, the third to net002.log etc. up to the maximum value of DB_LOGVER.
DB_LOGVER is set in the conf/recital.conf file:
DB_LOGVER=10; export DB_LOGVER
Enabling Log Files: Recital Universal Application Server for OpenVMS
To enable the system log file for the Recital Universal Application Server for OpenVMS, include the following command in the db_uas:config.db file:
set syslogging on
To set up Client/Server logging, one or more of the following symbols can be added to the <em>db_uas:login.com</em> file. The Recital Server must be restarted before symbol changes will be recognized. Each symbol should be set to the name of a log file.
Symbol
Logs Activity of…
UASLOG_PORT
Port Server (db_rsiserver)
UASLOG_NET
(Net) Server (db_netserver)
UASLOG_ORA
Oracle Server (db_oraserver)
UASLOG_INF
Informix Server (db_infserver)
UASLOG_ING
Ingres Server (db_ingserver)
UASLOG_JDB
JDBC Server (db_jdbserver)
UASLOG_REC
Recital Server (db_recserver)
Extract from db_uas:login.com
$ uaslog_port :== port.log $ uaslog_net :== net.log $ uaslog_ora :== ora.log $ uaslog_inf :== inf.log $ uaslog_ing :== ing.log $ uaslog_jdb :== jdb.log $ uaslog_rec :== rec.log
DB_LOGDIR
If the symbol DB_LOGDIR is set to an existing directory, all log files will be written to this directory. If not, the log files will be created in the UAS directory.
DB_LOGDIR is set in the db_uas:login.com file. By default it is set to the UAS.log] directory:
$db_logdir :== 'db_root'.log] ! system logging directory
DB_LOGVER
If the symbol DB_LOGVER is enabled, version numbers are added to the file names. For example, the activity of the first Net Server process will be logged to net.log, the second to net001.log, the third to net002.log etc.
DB_LOGVER is set in the db_uas:login.com file:
$db_logver :== true ! enable multiple log files
Enabling Log Files: Recital for Linux
To enable the system log file for Recital for Linux, include the following command in the conf/config.db file:
set syslogging on
Enabling Log Files: Recital for UNIX
To enable the system log file for Recital for UNIX, include the following command in the conf/config.db file:
set syslogging on
Enabling Log Files: Recital for OpenVMS
To enable the system log file for Recital for OpenVMS, include the following command in the db_ovd:config.db file:
set syslogging on
In Brief
- Log files provide important information to aid problem resolution, but they are also an overhead, so logging should only be enabled when required, not in normal production operation.
- The System log provides a system-wide view of logins, exits and error codes.
- The System log can be viewed in table format via the SYSLOGGING System Table.
- The System log is enabled using the SET SYSLOGGING ON Recital/4GL command in the conf/config.db file.
- Client/Server logs provide detailed information on client/server requests and responses.
- Client/Server logs are enabled using environment variables, symbols or Registry entries or by specifying the 'logging' parameter when starting the Recital Server.
- The location of log files is determined by the DB_LOGDIR setting.
- Versioning of log files is determined by the DB_LOGVER setting.
In this article Barry Mavin explains step by step how to setup a Linux HA (High Availability) cluster for the running of Recital applications on Redhat/Centos 5.3 although the general configuration should work for other linux versions with a few minor changes.
RTOS()
Syntax
RTOS( [ <workarea> ] )Description
The RTOS() function returns all the fields in the current row as a string. The string will begin with the unique row identifier and then the deleted flag, followed by the data in the record. An optional workarea can be specified, otherwise the current workarea will be usedExample
use backup in 0
use accounts in 0
nrecs=reccount()
for i = 1 to nrecs
if rtos(accounts) != rtos(backup)
debug("record "+recno()+" don't match")
endif
next
A quick tip for optimizing TCP performance on linux.
edit /etc/sysctl.conf add the lines:
If using gigabit ethernet:
net.ipv4.tcp_mem= 98304 131072 196608
net.ipv4.tcp_window_scaling=1
net.core.wmem_default = 65536
net.core.rmem_default = 65536
net.core.wmem_max=8388608
To reload these use:
# sysctl -p
If using infiniband:
net.ipv4.tcp_window_scaling=1
net.ipv4.tcp_timestamps=0
net.ipv4.tcp_sack=0
net.ipv4.tcp_rmem=10000000 10000000 10000000
net.ipv4.tcp_wmem=10000000 10000000 10000000
net.ipv4.tcp_mem=10000000 10000000 10000000
net.core.rmem_max=524287
net.core.wmem_max=524287
net.core.rmem_default=524287
net.core.wmem_default=524287
net.core.optmem_max=524287
net.core.netdev_max_backlog=300000